It is known that in industrial production processes, parts, such as workpieces, components or modules, are often assembled to a final product or unit. Examples include mounting of electrical components on a board and the assembly of a car body. Such assembly processes can be done automatically by machines including a gripper tool for grasping a part, for example, from a conveyor or a supply box and moving it into a desired position in relation to another part for mounting them together. Several machines can be involved in such an assembly process and some of the production steps can be done manually.
A gripper tool can include at least one gripper finger, which can be moved towards at least one other gripper finger or, for example, a wall or wrist of the gripper tool, so that a part or workpiece to be gripped can be clamped in between a variable gap formed, for example, by two gripper fingers. The shape of a gripper finger can depend on a size and shape of the object to be gripped. A gripper finger might be shaped similar to a human finger, for example, a simple rod with a length from a few cm to 50 cm and more, whereas the parts to be gripped can be clamped at the end of such a gripper finger. The shape of a gripper finger can be linear but also can include one or more individual bends to optimize it for the individual frame conditions, for example, the average size of the workpieces to be gripped.
A gripper finger or tool can be optimized for a special shape of a large object, such as a door of a car. In this case, the gripper finger might be suitable only for the gripping of this one special shape.
In production lines for smaller units, such as an assembly line for electrical components, a wide range of different shaped parts have to be gripped. For example resistors, integrated circuits, different shaped capacitors and others. To assure a correct assembly process, it can be required to have such parts in an exact defined position when clamped between, for example, two gripper fingers.
Therefore, a cast-like fixture can be provided at the surface area of a gripper finger, which is foreseen for clamping. So the object which is gripped, for example out of a supply box, is in an exact position without any larger tolerance when clamped in between the cast fixtures at the surface areas of the gripper fingers.
Such a gripper finger with a casted surface area for clamping may be suitable only for a limited range of shapes of workpieces to be gripped, in a worst case only for one shape. Therefore, different gripper fingers or gripper tools are used for different types of workpieces to be gripped. It can involve additional effort to provide several gripper fingers for respective gripper tools. It can involve additional time in the production process to change a gripper finger for a respective gripper tool to adapt the machine for the shape of another workpiece to be gripped.